I really think this is a good example of a grow out. I love how the undercut allows the circumvention of the weird bushy spots that happen when you try to grow everything out. I think the top of the back should have been left a tad long to allow for some back grow out and the undercut should be more toward the basis of the head near the neck like undercuts for long hair. But overall I th ink this (including the short cut above the ears is great